The role of oocyte organelles in determining developmental competence

The ability of an oocyte to undergo successful cytoplasmic and nuclear maturation, fertilisation and embryo development is referred to as the oocyte’s quality or developmental competence. Quality is dependent on the accumulation of organelles, metabolites and maternal RNA during the growth and maturation of the oocyte. Various models of good and poor oocyte quality have been used in order to understand the essential contributors to oocyte developmental success. This review describes these models and assesses their usefulness for studying the intrinsic quality of an oocyte. It then reviews the current knowledge of differences in oocyte organelle quantity and structure between good and poor quality oocytes. This provides a foundation for identifying key metabolic and potentially other mechanisms important for the development of a high quality oocyte.